Maintenance cart with air filtration

ABSTRACT

A maintenance/construction cart that facilitates wall and ceiling access while isolating the interior of the cart from the surrounding environment. The cart is configured such that its height can be easily adjusted by an operator to provide access to ceilings of different heights while maintaining the seal between the interior of the cart and the surrounding environment while structurally supporting a ladder leaning against a surface of the cart. In some embodiments, the cart includes an air filtration unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/217,857 entitled “Maintenance Cart with Air Filtration”, filed Dec.12, 2018, which is a continuation application of U.S. patent applicationSer. No. 15/400,440 entitled “Methods of Operating Maintenance Cartswith Air Filtration”, filed Jan. 6, 2017, now U.S. Pat. No. 10,195,979,which is a divisional patent application of U.S. patent application Ser.No. 14/744,691 entitled “Maintenance Cart with Air Filtration”, filed onJun. 19, 2015, now U.S. Pat. No. 9,574,399, which is related to andclaims priority benefits from U.S. Provisional Application Ser. No.62/025,208 entitled “Maintenance Cart with Air Filtration,” filed onJul. 16, 2014, all of which are incorporated in their entireties by thisreference.

FIELD OF THE INVENTION

This invention relates to devices and methods for facilitating wall andceiling access while providing air filtration to contain and capturehazardous and/or non-hazardous particulate, biological, and gas phasecontaminants released into the air as a result of these activities.

BACKGROUND

Similar to virtually any building, healthcare facilities, such ashospitals, require construction and maintenance including tasksnecessitating access to areas that cannot be regularly cleaned, such aswithin walls or above a ceiling. However, unlike many other facilities,healthcare and other facilities include requirements related tocleanliness and minimizing the risk of hospital acquired infections(HAIs) caused by hazardous airborne contaminants. There is a need toprotect patients and employees from exposure to construction particlesthat can potentially transmit airborne infectious diseases.

The design of products, such as maintenance/construction carts, thatfacilitate wall and ceiling access in sensitive environments ischallenging because there are a large number of demanding requirementsand desired features, some of which compete with each other. Forinstance, in addition to isolating the non-sanitizedconstruction/maintenance environment from the sanitary healthcareenvironment, it is desirable that such products be compact, lightweight,easily transported, powered, operated, maintained, cleaned, and stored.It is desirable that these products be durable and able to function innumerous different environments, as well as economical to purchase andoperate.

SUMMARY

The terms “invention,” “the invention,” “this invention” and “thepresent invention” used in this patent are intended to refer broadly toall of the subject matter of this patent and the patent claims below.Statements containing these terms should be understood not to limit thesubject matter described herein or to limit the meaning or scope of thepatent claims below. Embodiments of the invention covered by this patentare defined by the claims below, not this summary. This summary is ahigh-level overview of various aspects of the invention and introducessome of the concepts that are further described in the DetailedDescription section below. This summary is not intended to identify keyor essential features of the claimed subject matter, nor is it intendedto be used in isolation to determine the scope of the claimed subjectmatter. The subject matter should be understood by reference toappropriate portions of the entire specification of this patent, any orall drawings and each claim.

Disclosed is a maintenance/construction cart that facilitates wall andceiling access while isolating the interior of the cart from thesurrounding environment. The cart is configured such that its height canbe easily adjusted by an operator to provide access to ceilings ofdifferent heights while maintaining the seal between the interior of thecart and the surrounding environment and structurally supporting aladder leaning against a surface of the cart.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present invention are described indetail below with reference to the following drawing figures.

FIG. 1 is a perspective view of the front, top, and left side of amaintenance/construction cart according to one embodiment of thisinvention, shown with the upper structure in the raised position.

FIG. 2 is a perspective view of the rear, top, and left side of the cartdepicted in FIG. 1.

FIG. 3 is a partial perspective view of the front, top, and left side ofthe upper structure of the cart depicted in FIG. 1, shown with thesealing members removed.

FIG. 4 is a partial perspective view of the front, bottom, and left sideof the upper structure of FIG. 3.

FIG. 5 is a perspective view of a portion of themaintenance/construction cart depicted in FIG. 1, shown with variouscomponents removed.

FIG. 6 is a perspective view of a non-limiting embodiment of a pulleysystem positioned within the maintenance/construction cart depicted inFIG. 1.

FIG. 7A is a perspective view of a portion of the floor of the cartdepicted in FIG. 1, shown without a cover.

FIG. 7B is an enlarged view of a portion of FIG. 7A, taken at insetsquare 7B.

FIG. 7C is a perspective view of the portion of the floor of FIG. 7A,shown with a cover.

FIG. 8 is another perspective view of the rear, top, and right side ofthe maintenance/construction cart depicted in FIG. 1, shown with theupper structure in the partially lowered position and with variouscomponents removed.

FIG. 9 is a close-up view of the rear side of the cart depicted in FIG.8.

FIG. 10 is a close-up view of the rear side of the cart depicted in FIG.9, shown with an access door.

FIGS. 11 and 12 are close-up views of two recesses of the cart depictedin FIG. 1.

FIG. 13 is a perspective view of the front, top, and left side of themaintenance/construction cart depicted in FIG. 1, shown with the upperstructure in the partially lowered position and with various componentsremoved.

FIG. 14 is a side view of the maintenance/construction cart depicted inFIG. 13.

FIG. 15 is another perspective view of the front, top, and left side ofa maintenance/construction cart depicted in FIG. 1 with a non-limitingembodiment of a sealing member.

DETAILED DESCRIPTION

The subject matter of embodiments of the present invention is describedhere with specificity to meet statutory requirements, but thisdescription is not necessarily intended to limit the scope of theclaims. The claimed subject matter may be embodied in other ways, mayinclude different elements or steps, and may be used in conjunction withother existing or future technologies. This description should not beinterpreted as implying any particular order or arrangement among orbetween various steps or elements except when the order of individualsteps or arrangement of elements is explicitly described.

FIGS. 1-14 illustrate an exemplary embodiment of amaintenance/construction cart 100 that facilitates wall and ceilingaccess while isolating the maintenance/construction cart 100 from thesurrounding environment. As described in more detail below, the heightof the maintenance/construction cart 100 can be infinitely adjusted toallow access to and physical sealing contact with ceilings of differentheights, and the cart is configured so that its interior is sealed fromthe surrounding environment.

As illustrated in FIGS. 1-2, maintenance/construction cart 100 includesa lower structure 101 with side walls 102 that extend from floor 106.Side walls 102 and floor 106 are constructed with respect to lowerstructure 101 to seal the interior of the cart 100 from the surroundingenvironment to reduce the transmission of hazardous airbornecontaminants from the inside of cart 100 into the surroundingenvironment.

Lower structure 101, floor 106, and/or side walls 102 may be formed ofany suitable material including, but not limited to, aluminum, anodizedaluminum, steel, stainless steel, aramid fibers, Lexan, polycarbonate,polypropylene, other metallic or sheet metal materials, compositematerials, or other materials. One or more of the side walls 102 mayinclude an access door 103 that provides access to the interior of thecart 100. Any suitable portion of the one or more side walls 102 may betransparent as desired, such as transparent portions 104. If desired,the lower structure 101 may include one or more handgrips 116 tofacilitate transport of the cart 100. As shown in FIGS. 1 and 2, lowerstructure 101 may include two handgrips 116 at each corner (a total ofeight) or any suitable number and arrangement of handgrips.

As shown in FIGS. 1-4, cart 100 also includes an upper structure 300above an upper portion 105 of lower structure 101. As described in moredetail below, a plurality of structural members (e.g., telescoping posts306 in the illustrated embodiment) connect the upper structure 300 tothe upper portion 105 of the lower structure 101 and enable the upperstructure 300 to move relative to the lower structure 101. Specifically,upper structure 300 is configured to move between a stowed position(see, e.g., FIGS. 13 and 14) and a raised position (see, e.g., FIGS. 1and 2) relative to the lower structure 101. In this way, movement ofupper structure 300 allows for adjustment of the overall height of thecart 100. FIGS. 1 and 2 illustrate the upper structure 300 in a raisedposition that facilitates access to a maintenance area generallycorresponding to the height of the cart 100 when in the raised position,for example, but not limited to, 10-foot ceilings, 12-foot ceilings, ortaller or shorter ceilings. FIGS. 13-14 illustrate the cart 100 in thestowed position, with upper structure 300 adjacent the upper portion 105of the lower structure 101, reducing the overall height of the cart 100and allowing cart 100 to be easily maneuvered and pass through doorways.

The upper structure 300 is configured so that it may be adjusted to anysuitable height between the stowed position and the raised position asdesired. FIG. 8 illustrates the cart 100 in a position between thestowed position and the raised position. Upper structure 300 may beformed of any suitable material including, but not limited to, aluminum,anodized aluminum, steel, stainless steel, aramid fibers, Lexan,polycarbonate, polypropylene, other metallic or sheet metal materials,composite materials, or other materials.

Moreover, upper structure 300 is configured as a rigid and structurallysecure structure that serves as an independent support for a ladder(such as ladder 108 described below) that is positioned against upperstructure 300, as described below. In particular, upper structure 300 isdesigned to receive and support an end of ladder 108 at a proper anglewithout bending, deflection, rocking, or vibration. For example, thecart 100 and upper structure 300 are configured such that a 300 lb.person can safely stand on a ladder without any safety concerns.

As illustrated in FIGS. 1-5, the upper structure 300 includes four sideshaving a substantially vertical structural member (e.g., telescopingposts 306 in the illustrated embodiment), which may be located at eachcorner of the upper structure 300. Moreover, each side of the upperstructure 300 may have an efficient box-frame structural design thatincludes an inner member 321, an outer member 322, an upper member 323,and a lower member 324 connected to one another (forming a box-shapedcross-section). Such a structural design helps ensure that the upperstructure 300 can withstand bending and shear loads applied due tovarious loading conditions based on a person standing on ladder. In someembodiments, the upper structure 300 is approximately 4 to 12 inchestall. In some embodiments, the upper structure 300 is approximately 8inches tall. The structural rigidity of cart 100 can be further enhancedwhen the upper structure 300 is pressed upward against a surface.

In some embodiments, the upper structure 300 includes a ladder supportunit configured to receive and support an end of a ladder, such asladder 108. As shown in the embodiment of FIG. 5, one example of theladder support unit is ladder support bracket 310, which interfaces withan upper portion of ladder 108. In some embodiments, ladder supportbracket 310 is attached to the upper structure 300 using two sidesupport brackets 312 and center support bracket 313, although laddersupport bracket 310 may be attached to upper structure 300 in anysuitable way. The upper portion of ladder 108 rests against rear surface311 of ladder support bracket 310. The ladder support bracket 310 mayalso include one or more ladder securing mechanisms 314 such as a taband/or a strap configured to secure the ladder 108. In some embodiments,ladder securing mechanism 314 includes a strap that loops around theladder 108 and that can be fastened using hook and loop or any otherfastening means. Another example of securing mechanism 314, asillustrated in FIG. 5, is a plurality of tabs 314, which are disposedsubstantially parallel to rear surface 311 such that ladder 108 can betrapped between rear surface 311 and tabs 314. Such an arrangement cansecure the ladder and keep the ladder from moving laterally or fore/aft.The tabs 314 may be permanently attached, removeably attached, orhingedly attached. If the tabs 314 are permanently attached, the ladder108 must be inserted between rear surface 311 and tabs 314. If the tabs314 are removeably or hingedly attached, the tabs 314 may be secured ina deployed position using pins, conventional/quick-release fasteners, orany other fastening means.

As shown in FIGS. 3 and 4, upper structure 300 also includes an opening303 that extends from a lower surface 301 of the upper structure 300 toa top surface 302 of the upper structure 300 to permit access from theinterior of cart 100 to a ceiling, wall, or other structure external tocart 100. As shown in FIGS. 1 and 2, a cover 121 may extend across theopening 303 to control access through opening 303 and seal the interiorof the cart 100 from an environment surrounding the cart 100 when thecart 100 is not arranged with opening 303 adjacent to a ceiling, wall,or other structure external to cart 100. The cover 121 may bepermanently or removably coupled to upper structure 300 in any suitableway, for example, but not limited to, using slide fasteners such aszippers, hook and loop fasteners, pivoting means, sliding means, sealingmeans, any type of mechanical fastener, etc. Although cover 121 isillustrated as positioned along top surface 302, cover 121 may bedisposed at lower surface 301 or at any position where the cover 121 cancover opening 303. The cover 121 may be constructed from any suitablematerial such as, but not limited to, plastic with reinforced scrim,Nomex®, aluminum, steel, aramid fibers, other types of plastic, othermetallic or sheet metal materials, composite materials, or othersuitable materials. The cover 121 may be transparent, translucent, oropaque.

In some embodiments, the upper structure 300 may include a gasket 120around a perimeter of top surface 302. When placed adjacent to aceiling, the gasket 120 compresses to form a seal between the upperstructure 300 and the ceiling to ensure that any harmful particles orcontaminants are directed into the interior of cart 100 to be filteredand not released into the surrounding environment. The gasket 120 maybe, for example, a one inch closed cell neoprene gasket or any othersuitable gasket.

Cart 100 also includes an upper structure adjustment mechanism thatmoves the upper structure 300 between the stowed position and the raisedposition or any suitable position between the stowed and raisedpositions. In some embodiments, the upper structure adjustment mechanismis configured to move some or all of the structural members generallysimultaneously so that the upper structure 300 remains generally levelduring its movement. Although a single upper structure adjustmentmechanism is illustrated herein, multiple upper structure adjustmentmechanisms may be used. In some embodiments, the upper structureadjustment mechanism helps maintain the top surface 302 in anapproximately parallel relationship with upper portion 105 of lowerstructure 101. One non-limiting example of an upper structure adjustmentmechanism is a pulley system, although any suitable adjustment mechanismmay be used. One non-limiting example of a suitable pulley system isillustrated and described below, but it should be understood that anysuitable pulley system or other adjustment mechanism may be used.

The structural members that connect the upper structure 300 to the upperportion 105 of the lower structure 101 each may be a single solidmember, a telescoping member, or any suitable component. One example, asshown in FIGS. 1-2, includes four telescoping posts 306 that connectupper structure 300 to upper portion 105 of lower structure 101 and areconfigured to telescope to move upper structure 300 between its stowedposition and its raised position (or any suitable positiontherebetween). Although a telescoping post 306 is illustrated aspositioned at each of the four corners of lower structure 101,telescoping posts 306 may be positioned in other locations along lowerstructure 101 and any suitable number of telescoping posts may be used.As shown in FIG. 4, each telescoping post 306 includes an upper portion307, a middle portion 308, and a lower portion 309 that move withrespect to one another (i.e., telescope) as needed to raise and lowerupper structure 300. Telescoping post 306 may have any suitable numberof telescoping portions.

As shown in FIGS. 6-10, pulley system may include any suitable number ofcables 350 disposed in telescoping posts 306 and routed through one ormore pulleys to an actuator, such as winch 118 and hand crank 119 (FIGS.9-10). As illustrated, each telescoping post 306 includes a separatecable 350, although any suitable number of cables may be used. Actuationof the winch 118 moves the one or more cables 350, which in turn causesone or more of the telescoping posts 306 to move. In some embodiments,winch 118 is configured to spool the cables 350 such that eachtelescoping post 306 extends or contracts generally simultaneously withthe other telescoping posts 306 resulting in smooth and level verticalmovement of the upper structure 300 in the desired direction.

In the non-limiting embodiment of FIG. 6, each telescoping post 306includes an upper telescoping pulley 351 and a lower telescoping pulley352. Each cable 350 has an end 357 that may be attached to a fitting 357located adjacent to or inside the respective telescoping post 306 or maybe otherwise secured. As shown in FIGS. 6, 7A, and 7B, after interfacingwith lower telescoping pulley 352, the cable 350 passes through floor106 and interfaces with a floor pulley 353, shown in FIGS. 7A and 7B.The floor pulleys 353 redirect the cables 350 approximately ninetydegrees from a vertical direction into a horizontal plane such that theyultimately connect with a winch pulley 355. In some embodiments, any orall of cables 350 may pass through intermediate pulleys 354 beforepassing through the winch pulley 355. As illustrated, the winch pulleys355 redirect each cable 350 approximately ninety degrees and upwardtoward the winch 118. The arrangement and number of pulleys can vary andare not limited to the embodiment illustrated.

As shown in FIG. 7C, a cover 356 may be disposed adjacent to eachtelescoping post 306 to cover the cable 350 and keep dirt and/or foreignobjects out of the upper structure adjustment mechanism. In addition toprotecting the upper structure adjustment system as described above, theuse of covers 356 may facilitate decontamination procedures bysimplifying the internal surfaces to be cleaned.

If more than one cable 350 is used, the cables 350 may be consolidatedusing fittings to reduce the number of cables 350 that attach to thewinch 118. For example, in some embodiments, the cables corresponding totwo opposite posts are connected (i.e., the left front cable and theright rear cable are connected). Such a pairing of cables 350 provides apotential failsafe such that, in the event of a failure, the remainingcables 350 (including two opposite cables 350) are still operational toraise and lower the upper structure 300.

In some embodiments, as shown in FIGS. 8-10, the winch 118 may be geardriven and may be disposed in a winch compartment 117. The winchcompartment 117 may include a winch access door 114 that restrictsaccess to winch 118 but that can be removed/opened to conductmaintenance operations related to the winch 118 or cable 350. As shownin FIGS. 9 and 10, whether winch access door 114 is open or closed, auser may actuate the winch 118 by interfacing with a gear train forspooling the cable 350 and thus raising/lowering the upper structure300. One example of an actuator 119 for interfacing with the gear train,as illustrated in FIG. 10, is a hand crank. Other non-limiting examplesinclude corded or cordless drills, manual or power ratchets, pneumatictools, integral motors, or any other suitable mechanism to actuate winch118.

The use of a winch to actuate movement of the telescoping posts 306allows a single operator to raise/lower the upper structure 300 easilyand while keeping the upper structure 300 level relative to the lowerstructure 101. The use of a gear driven winch also provides an inherentbraking to ensure that upper structure 300 does not fall or move tooabruptly. Although the actuator 119 is illustrated as external to cart100, as an alternative, the cart 100 may be configured such that theactuator 119 is accessible from inside the cart 100. In addition, thecart 100 may be configured to allow access to actuator 119 from bothinside and outside of the cart 100.

As mentioned, the upper structure adjustment mechanism is not limited tothe pulley system described herein. Other methods and/or mechanisms maybe used to raise or lower the upper structure 300. Non-limiting examplesinclude systems that do or do not use cables including systems using asingle electric motor for operating winch 118, individual electricmotors for each telescoping post 306, hydraulic based systems, drivescrew based systems, pneumatic based systems, etc.

As illustrated in FIGS. 1 and 2, cart 100 also includes one or moresealing members 112 that extend between the upper portion 105 of thelower structure 101 and the upper structure 300 to seal the interior ofthe cart 100 from the surrounding environment as the upper structure 300moves out of its stowed position. Each of the one or more sealingmembers 112 includes a first end that attaches to the upper portion 105of the lower structure 101 and a second end that attaches to the upperstructure 300. Each of the one or more sealing members 112 compressesand expands based on movement of the upper structure 300 relative to thelower structure 101. As shown in FIG. 15, the one or more sealingmembers 112 may be configured without any predetermined or existingshape/structure (e.g., a flexible or rigid sheet). In some embodiments,as illustrated in FIGS. 1 and 2, each of the one or more sealing members112 may be flexible bellows that include a plurality of existing foldsconfigured to compress and expand based on movement of the upperstructure 300 relative to the lower structure 101 such that the one ormore sealing members 112 are configured to expand and contract similarto an accordion. In this way, the one or more sealing members 112 iscompliant and capable of moving with the upper structure 300. Forexample, as shown in FIGS. 1 and 2, the one or more sealing members 112expand when the upper structure 300 is raised to a 10-foot (or anyheight) ceiling and compress and/or fold when the upper structure 300lowers to the stowed position to contact the lower structure 101 (FIGS.13 and 14).

The one or more sealing members 112 may be formed of any suitablematerial including, but not limited to, rigid plastic, soft plastic,plastic with scrim reinforcement, Nomex®, aluminum, steel, aramidfibers, other metallic or sheet metal materials, other plasticmaterials, composite materials, or other similar materials. In someembodiments, the one or more sealing members 112 may include a firerating or a fire-resistance rating and/or may be transparent,translucent, and/or opaque. In some embodiments, the one or more sealingmembers 112 are removable to facilitate decontamination procedures. Theone or more sealing members 112 may be connected to cart 100 in anysuitable way such that they seal the interior of the cart 100 from thesurrounding environment. As shown in FIG. 15, the one or more sealingmembers 112 may include one or more access panels 130 or openings. Theaccess panel/opening 130 may be opened and closed using slide fastenerssuch as zippers, hook and loop fasteners, pivoting means, sliding means,sealing means, or any type of mechanical fastener. Like the one or moresealing members 112, the access panel/opening 130 may include a firerating or a fire-resistance rating and/or may be transparent,translucent, and/or opaque. In some embodiments, the one or more sealingmembers 112 may be one or more rigid components inserted between theupper portion 105 of the lower structure 101 and the upper structure300. For example, the one or more sealing members 112 may be a set ofrigid polycarbonate panels configured to be inserted into mountingchannels along lower structure 101 and the upper structure 300.

As shown in FIGS. 1 and 2, cart 100 may include at least one airfiltration unit 111 disposed either outside or inside the lowerstructure 101. In the embodiment illustrated in FIG. 2, air filtrationunit 111 is adjacent to and/or connected to at least one or more ductunits 113 that communicate with the environment surrounding cart 100.Air filtration unit 111 helps capture and filter hazardous and/ornon-hazardous particulate, biological, and gas phase contaminantspresent within the interior of the cart 100. In some embodiments, airfiltration unit 111 may have the ability to create negative air pressureinside the cart 100. The cart 100 may be configured modularly such thatvarious products can be used for the air filtration unit 111. Onenon-limiting example of an air filtration unit 111 is the HEPA-AIRE®PAS600 Portable Air Scrubber offered by Abatement Technologies. The cart100 may be configured to include a remote variable control module forcontrolling air filtration unit 111 where the control module may bedisposed inside or outside the cart 100. The control module may be usedto change the speed of air filtration unit 111 to change or maintain aproper negative pressure within the cart 100. In some embodiments, thecontrol module is accessible while standing on ladder 108.

When located outside of cart 100, air filtration unit 111 is disposed onan auxiliary cart attached or connected to cart 100 such that theauxiliary cart does not need to be moved separately from cart 100. Theauxiliary cart allows for a wider range of product selection (e.g.,where a bigger high capacity unit may be required).

Because the cart 100 is capable of maintaining a negative air pressureinside the cart based on the operation of the air filtration unit 111,the cart 100 may include provisions to constrain the one or more sealingmembers 112 to prevent collapsing or significant deflection of thesealing members 112 toward the interior of cart 100. One example of sucha provision, as illustrated in FIG. 15, is one or more sleeves 131,which wrap around each structural member (e.g., telescoping post 306).The sleeves 131 constrain the one or more sealing members 112 to ensurethey do not significantly encroach on the space of the interior of cart100 such that a user is not hindered when conducting maintenanceoperations.

Cart 100 also includes one or more ladders 108 configured to reach theopening 303 of the upper structure 300 (see FIGS. 1 and 2) andfacilitate operator access to a ceiling or wall. The ladder 108 maytelescope or otherwise be adjustable in height, and/or be collapsible toa non-deployed position 109 for storage of the ladder. In someembodiments, the collapsible ladder 108 may be an extension ladder. Theladder 108, in certain embodiments, may be fiberglass, which isparticularly appropriate for electrical work. Other non-limitingexamples of materials for ladder 108 include aluminum, steel, and wood.In some embodiments, cart 100 may include a storage unit 110 configuredto hold the ladder 108 in the non-deployed position 109. In otherembodiments, the one or more ladders 108 may be configured to fold downfrom an upper portion of the cart 100.

In some embodiments, as shown in FIGS. 11 and 12, the floor 106 mayinclude one or more ladder securing units 400. The ladder securing units400 may be protrusions, non-skid/non-slip layers (applied using anadhesive layer or applied as a coating), recesses, or any suitablefeature or combination of features configured to secure a lower portionof ladder 108. One example, as illustrated in FIGS. 11 and 12, isrecesses 400, where each recess 400 may have a single cavity or aplurality of cavities (401, 402, etc.) configured to interface with alower portion of the ladder 108. The recess 400 may be configured withany suitable dimensions to match the foot of the ladder 108. Each cavitymay be configured to arrange the ladder 108 at a predetermined anglebased on a given height of the opening 303 of the upper structure 300.As shown in the embodiment of FIGS. 11 and 12, floor 106 includes a pairof recesses 400, each recess having a first cavity 401 and a secondcavity 402 configured to arrange the ladder at a different predeterminedangle (i.e., placing the lower portion of the ladder in the firstcavities 401 will arrange the ladder at a first predetermined anglewhile placing the lower portion of the ladder in the second cavities 402will arrange the ladder at a second predetermined angle that isdifferent from the first predetermined angle). For example, the firstcavities 401 may be configured to hold the ladder at an OSHA-compliantangle when the ladder is adjusted to interface with the upper structure300 when arranged for an 8.5-foot ceiling (or other height)configuration, and the second cavities 402 may be configured to hold theladder at an OSHA-compliant angle when the ladder 108 is adjusted tointerface with the upper structure 300 when arranged for a 10-footceiling (or other height) configuration. Optional dividers 403 may beused to separate the plurality of cavities from one another. Inaddition, if present, the plurality of cavities (401, 402, etc.)function as a safety feature to secure the ladder 108 and preventunwanted movement of the ladder 108. In some embodiments, each recess isconfigured without a divider 403 such that the lower portion of ladder108 can be disposed in the one or more recesses for various heights ofthe upper structure 300 while maintaining an acceptable (e.g., OSHAcompliant) ladder angle. As described above, ladder securing units 400may be protrusions such as lips, ridges, bars, or any feature orcombination of features configured to interface with the lower portionof ladder 108.

The cart 100 may, in some embodiments, include an electrical connectionunit 115 that provides electrical power to the cart 100. The electricalconnection unit 115 may be configured to supply power to coveredelectrical outlets that may be located inside and/or outside the cart100. The cart 100 may also include two or more casters 107 to facilitatemovement of the cart 100. In some embodiments, one or more of thecasters 107 include a lock. As shown in FIG. 4, the cart 100 may includea storage shelf 305 configured to move with the upper structure 300 orremain in a static position regardless of the position of the upperstructure 300. The storage shelf 305 is not present in some cases.

The cart 100 may include various other components such as an internallight, a pressure monitoring system, a detection and alarm system forwhen the upper structure 300 reaches a height limit (such as a ceiling)that may utilize a pressure or proximity switch, a cleaning/sanitizingsystem with compressed air, floor drains, a first aid kit, an eye washsystem, an adhesive mat near access door 103, and/or any other desiredcomponent or feature.

Any of the components of the cart 100 may be attached to one another viasuitable fasteners, which include, but are not limited to, screws,bolts, rivets, 3M® Very High Bond (VHB) tape, other acrylic foam tapes,or other mechanical or chemical fasteners. In some embodiments, thecomponents of the cart 100 are assembled using seals/gaskets to minimizeairflow thus reducing the transmission of hazardous airbornecontaminants from the interior of the cart to the external environment.

Different arrangements of the components depicted in the drawings ordescribed above, as well as components and steps not shown or describedare possible. Similarly, some features and subcombinations are usefuland may be employed without reference to other features andsubcombinations. Embodiments of the invention have been described forillustrative and not restrictive purposes, and alternative embodimentswill become apparent to readers of this patent. Accordingly, the presentinvention is not limited to the embodiments described above or depictedin the drawings, and various embodiments and modifications can be madewithout departing from the scope of the claims below.

That which is claimed:
 1. A maintenance cart comprising: a lowerstructure comprising a floor, an upper portion, and a plurality of sidesextending between the upper portion and the floor; an upper structuredisposed above the upper portion of the lower structure, wherein theupper structure comprises a plurality of structural members connectingthe upper structure to the lower structure, wherein the plurality ofstructural members are configured to position the upper structurebetween a stowed position and a raised position relative to the lowerstructure, wherein the stowed position comprises a minimum distancebetween the upper structure and the lower structure such that the upperstructure is adjacent the upper portion of the lower structure, whereinthe raised position comprises a maximum distance between the upperstructure and the upper portion of the lower structure, and wherein thelower structure and the upper structure together define a single,enclosed interior workspace: (i) when the upper structure is in thestowed position; and (ii) when the upper structure is in the raisedposition; and a ladder support bracket within the single, enclosedinterior workspace of the maintenance cart.
 2. The maintenance cart ofclaim 1, wherein the plurality of structural members comprisetelescoping members.
 3. The maintenance cart of claim 1, wherein theladder support bracket is attached to the interior of the maintenancecart, and wherein the ladder support bracket moveable such that at leasta portion of the ladder support bracket moves away from the lowerstructure.
 4. The maintenance cart of claim 1, wherein the laddersupport bracket is attached to the upper structure.
 5. The maintenancecart of claim 1, wherein the plurality of structural members are notwithin the single, enclosed interior workspace.
 6. The maintenance cartof claim 1, further comprising: at least one sealing member attached tothe upper structure and to the upper portion of the lower structure,wherein the at least one sealing member compresses and expands based onmovement of the upper structure relative to the lower structure, andwherein the at least one sealing member maintains a seal between thesingle, enclosed interior workspace of the maintenance cart and anenvironment surrounding the maintenance cart.
 7. The maintenance cart ofclaim 1, wherein movement of the upper structure relative to the lowerstructure changes a volume of the single, enclosed interior workspace.8. The maintenance cart of claim 1, further comprising a gasket sealthat forms a seal on a top surface of the upper structure against aceiling when the upper structure is in the raised position.
 9. Amaintenance cart comprising: a lower structure comprising a floor, anupper portion, and a plurality of sides extending between the upperportion and the floor; an upper structure disposed above the upperportion of the lower structure, wherein the upper structure comprises aplurality of structural members connecting the upper structure to thelower structure, wherein the plurality of structural members areconfigured to position the upper structure between a stowed position anda raised position relative to the lower structure, wherein the stowedposition comprises a minimum distance between the upper structure andthe lower structure such that the upper structure is adjacent the upperportion of the lower structure, and wherein the raised positioncomprises a maximum distance between the upper structure and the upperportion of the lower structure, and wherein at least one of theplurality of structural members moves the upper structure relative tothe lower structure; and a ladder support bracket configured tostructurally support a ladder extending from the lower structure throughthe upper portion of the lower structure and into the upper structure,wherein the lower structure and the upper structure together define asingle, enclosed interior workspace: (i) when the upper structure is inthe stowed position; and (ii) when the upper structure is in the raisedposition, and wherein the ladder support bracket is attached to at leastone of the upper structure or the lower structure within the single,enclosed interior workspace.
 10. The maintenance cart of claim 9,wherein at least one of the plurality of structural members is notwithin the single enclosed interior workspace when the upper structureis in the stowed position.
 11. The maintenance cart of claim 9, whereinthe upper structure further comprises an opening on an opposite end ofthe maintenance cart from the floor of the lower structure.
 12. Themaintenance cart of claim 11, wherein the upper structure furthercomprises a cover that is movable between a stowed position and adeployed position, wherein, in the stowed position, the cover permitsaccess to the single, enclosed interior workspace through the opening,and wherein, in the deployed position, the cover prevents access throughthe opening to the single, enclosed interior workspace.
 13. Themaintenance cart of claim 9, wherein the upper structure is verticallyabove the lower structure in both the stowed position and the raisedposition, and wherein the upper structure contacts the lower structurein the stowed position.
 14. The maintenance cart of claim 9, wherein theladder support bracket is moveable relative to the lower structure. 15.A maintenance cart comprising: a lower structure comprising an upperportion and a plurality of sides extending down from the upper portion;an upper structure disposed above the upper portion of the lowerstructure, wherein the upper structure comprises a plurality ofstructural members connecting the upper structure to the lowerstructure, wherein the plurality of structural members are configured toposition the upper structure between a stowed position and a raisedposition relative to the lower structure, wherein the stowed positioncomprises a minimum distance between the upper structure and the lowerstructure such that the upper structure is adjacent the upper portion ofthe lower structure, wherein the raised position comprises a maximumdistance between the upper structure and the upper portion of the lowerstructure, wherein at least one of the plurality of structural membersmoves the upper structure relative to the lower structure, and whereinthe lower structure and the upper structure together define a single,enclosed interior workspace: (i) when the upper structure is in thestowed position, and (ii) when the upper structure is in the raisedposition; and a ladder support bracket attached to at least one of theupper structure or the lower structure within the single, enclosedinterior workspace, wherein at least one of the plurality of structuralmembers is not within the single enclosed interior workspace when theupper structure is in the stowed position.
 16. The maintenance cart ofclaim 15, wherein at least a portion of the ladder support bracket isdisposed adjacent to the upper structure when the upper structure is inthe raised position.
 17. The maintenance cart of claim 18, wherein theladder support bracket is moveable relative to the lower structure. 18.The maintenance cart of claim 15, wherein at least one of the structuralmembers of the plurality of structural members move the upper structurerelative to the lower structure.
 19. The maintenance cart of claim 18,wherein at least two structural members of the plurality of structuralmembers move the upper structure relative to the lower structure. 20.The maintenance cart of claim 15, wherein the upper structure isvertically above the lower structure in both the stowed position and theraised position, and wherein the upper structure contacts the lowerstructure in the stowed position.